Daily Report for 21st May 2024

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Measure Value (anomaly) Time Month cumul. Record High Record Low
Minimum Temperature 11.1 °C (+1.3) 02:48 10.4 °C (+1.8) 13.5 °C (+3.7), 2016 5.5 °C (-4.3), 2015
Maximum Temperature 14.8 °C (-3.6) 16:17 19.7 °C (+2.3) 27.4 °C (+9.0), 2020 12.7 °C (-5.7), 2021
Mean Temperature 12.9 °C (-1.1) 15.0 °C (+2.0) 21.4 °C, 2020 11.3 °C, 2021
Minimum Humidity 84% 00:12 63% 84%, 2024 28%, 2020
Maximum Humidity 96% 23:56 94% 96%, 2024 81%, 2015
Mean Humidity 91% 80% 91%, 2024 55%, 2011
Minimum Pressure 1009 hPa 23:54 1011 hPa 1029 hPa, 2010 996 hPa, 2021
Maximum Pressure 1013 hPa 00:20 1016 hPa 1032 hPa, 2010 1002 hPa, 2021
Mean Pressure 1011 hPa 1014 hPa 1030 hPa, 2010 998 hPa, 2021
Mean Wind Speed 2.4 mph (-2.3) 3.6 mph (-1.1) 13.9 mph, 2021 2.2 mph, 2018
Maximum Wind Speed 7.1 mph 06:28 10.9 mph 23.5 mph, 2021 7.1 mph, 2024
Maximum Gust 11.5 mph 00:12 16.6 mph 42.2 mph, 2021 11.5 mph, 2024
Mean Wind Direction NNE
Rainfall 18.8 mm 52.0 mm (167%) 18.8 mm, 2024
Maximum Hourly Rain 6.6 mm 20:29 6.6 mm, 2024
Maximum 10-min Rain 2.0 mm 19:54 2.0 mm, 2024
Maximum Rain Rate 60 mm/h 19:49 60 mm/h, 2024
Minimum Dew Point 9.2 °C 02:31 8.5 °C 9.5 °C, 2010 1.2 °C, 2015
Maximum Dew Point 13.7 °C 16:16 13.8 °C 15.5 °C, 2020 7.6 °C, 2015
Mean Dew Point 11.5 °C 11.3 °C 12.2 °C, 2010 3.8 °C, 2015
Measure Value Time Month cumul. Record High Record Low
Night Minimum (21-09) 11.1 °C 02:48 10.4 °C 13.5 °C, 2016 5.5 °C, 2015
Day Maximum (09-21) 14.8 °C 16:16 19.7 °C 27.4 °C, 2020 12.7 °C, 2021
Max 10m Temp Rise 0.3 °C 12:57 0.9 °C 1.7 °C, 2010 0.3 °C, 2024
Max 1hr Temp Rise 0.9 °C 13:47 2.6 °C 5.7 °C, 2011 0.9 °C, 2024
Max 1hr Hum Rise 3% 01:30 8% 14%, 2018 3%, 2024
Max 10m Temp Fall 0.3 °C 00:33 0.5 °C 1.0 °C, 2010 0.2 °C, 2012
Max 1hr Temp Fall 1.1 °C 01:16 1.7 °C 2.4 °C, 2020 0.7 °C, 2012
Max 1hr Hum Fall 2% 10:46 11% 25%, 2010 2%, 2024
Max 10m Wind Speed 5.2 mph 00:16 8.1 mph 18.3 mph, 2021 5.2 mph, 2024
Minimum Feels-like 12.0 °C 02:27 10.5 °C 15.1 °C, 2020 3.0 °C, 2015
Maximum Feels-like 18.0 °C 16:11 22.6 °C 29.8 °C, 2020 13.1 °C, 2021
Mean Feels-like 15.0 °C 16.9 °C 23.3 °C, 2020 11.6 °C, 2021
Air-frost Hrs 0 hrs 0 hrs 0 hrs, 2009 0 hrs, 2009
Measure Value (anomaly) Month cumul. Record High Record Low
Temperature Range 3.7 °C (-4.9) 9.3 °C (+0.5) 14.6 °C (+6.0), 2015 2.8 °C (-5.8), 2021
Humidity Range 12% 31% 58%, 2020 12%, 2024
Pressure Range 4 hPa 5 hPa 10 hPa, 2014 2 hPa, 2012
Measure Value [% of max] Month cumul. Record High Record Low
Sun Hours 0 [0%]119 hrs (94%) [40%] 13.5 [94%], 2011 0 [0%], 2021
Wet Hours 9
[Mean rain rate: 2.1 mm/h]
36 hrs (133%) [7.1%] 9, 2024 0, 2009
Cloud Cover unknown
Events None
Comments data is awaiting quality control from site operator
Extra Comments
Issues None known
Observer Absent? Yes - observations may be unreliable
Pond Temperature (Heath) 17.5 °C
Notes
Detailed daily weather report for Hampstead nw3 in London on 21st May 2024.
Times of extremes are computed using the midpoint of the longest continuous period at that extreme value.
Cumulative anomalies are reported according to the expected value for the month-to-date rather than month-end.
Sun hrs are derived based on analysis of webcam observations, but may use data from our closest site, Heathrow, when needed.
Wet hrs are dervied algorithmically from rainfall data, though may be adjusted manually.
Rainfall totals may be manually adjusted after the fact to correct delayed or erroneous data.
Cloud cover and Events are manually reported, often with multi-week delays.
Data is generally reliable and accurate but should always be viewed with some quantity of salt to hand.
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Daily Graph of Conditions

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